Focus on Impacts

Jonathan L. Scheuer (Consultant)

While the high islands of Hawai`i are wetter than much of the western United States, Hawai`i has a similar regional history of intense legal fights over water. Ongoing conflicts illustrate not only how sectors and players compete, but also show how changes in the abundance and distribution of water caused by climate change may intensify these prolonged battles.

Figure 2.21. In Maui’s `Īao Valley, conservationists and small farmers would like to restore historic streamflows away from plantation-era diversions that capture all base flow. Proponents of restoring historic flow levels would like to use the water for traditional cultural and agricultural practices and for restoring the habitat of native species. Photo courtesy of Jonathan L. Scheuer.

Contemporary conflicts over water allocation in Hawai`i have their origins in the mid-1800s, when King Kamehameha III created private property in land but continued to hold water as a public trust, setting the stage for conflict between emerging water-intensive agribusiness and traditional users. Today’s battles take place under a legal framework that includes judicial precedent (including decisions made during the Hawaiian Kingdom) (Hawai`i Revised Statures [HRS] 1-1), State constitutional provisions that reiterate the public trust in water and Native Hawaiian rights (Haw. Const. art. XI, § 1 & 7, art. XII §1-4 & 7), and the state’s Water Code (HRS 174C). The state Commission on Water Resource Management attempts to balance public trust uses of water (including traditional and customary Hawaiian practices, the procreation of fish and wildlife, and the maintenance of ecological balance and scenic beauty) against a goal of maximizing beneficial uses (including agricultural, commercial, and industrial consumption).

The largest ongoing fight has been on the island of O`ahu, where the Waiāhole Ditch system was developed in 1913–1916 to deliver water from the wet, windward Ko`olau Mountains to the dry, southern leeward plain for sugar cultivation. While originally designed to capture stream water, the construction of the delivery tunnels pierced large volcanic dike compartments (Fig. 2.21), releasing stored groundwater and over time changing the underlying hydrology of windward streams (Takasaki and Mink, 1985). Beyond the immediate impact on ecosystems, this significantly disrupted nutrient flow into Kāne`ohe Bay, the largest estuarine system of the Pacific Islands (in re Water Use Permit Applications, 94 Haw. 97 P.3d 409(2000)).

The current battle ignited in 1995 with the closure of the plantation using this water. Before the Commission on Water Resource Management and later the Hawai’i Supreme Court, leeward interests (including groups in the agricultural, development, military, and tourism sectors) sought to maintain ditch flows, while conservationists, Native Hawaiians, and small riparian farmers sought to restore windward streams. The current allocation restores approximately one-half of the water to the streams of origin. The years of litigation have cost millions of dollars, and today, the case is on its third appeal to the Hawai`i Supreme Court.

The Hawai`i Supreme Court’s decisions affirm a public trust in water and demand adherence to the precautionary principle in managing the trust. Decisions up to now, however, have not taken into account the decline in rainfall and base flow observed over the past 60 years (Oki, 2004) or effects from other threats to forested recharge areas.

An ongoing battle on Maui is even more intense because of concerns about groundwater available for the island’s human population. Small riparian farmers and conservationists have sought regulation of groundwater withdrawals and restoration of streamflows from historic plantation diversions that were designed to capture 100% of base flows (Figure 2.21). This battle has pit developers, agribusiness interests, and the county against small farmers, Native Hawaiians, and conservationists. It has been before the Commission on Water Resource Management and is currently on appeal to the Hawai`i Supreme Court (Commission on Water Resource Management, 2010).

As on O`ahu, rainfall and base flow on Maui show a statistically significant long-term decline. Recent data (Giambelluca et al., 2011) suggest that this trend could continue, with profound consequences for the island’s water resources.

On the leeward side of Hawai`i Island, an emerging dispute over the allocation of water focuses on the effects of water use on groundwater-dependent ecosystems. Water demand is being driven by significant resort, commercial, and residential development. According to the 2010 US Census, population in the North Kona and South Kohala areas increased more than 30% in the past decade. With few streams on this part of the island, water needs must be met by groundwater. The underlying

Figure 2.22. Anchialine pools, such as the Kūki‘o Pools on Hawai‘i Island, are unique environments found only in the coastal tropics and sub-tropics. The pools have no surface connection to the ocean, yet can range from fresh to brackish. Anchialine pools are critical habitat for several rare and endemic species such as opae’ula red shrimp, snails, and insects. Photo courtesy of Rosa Sey.

hydrology is poorly understood, however, and the state’s calculation of sustainable yields depends on a simple mathematical model (Oki & Meyer, 2001). Water-planning documents that estimate consumption show demand likely to outstrip supply in most growth scenarios (Hawai`i County, 2010).

Important coastal resources with dual ecological and cultural significance depend on groundwater. These include anchialine pools (Figure 2.22), coral reefs, and Native Hawaiian fishponds. They may be significantly affected by increased groundwater withdrawals (Oki et al., 1999). Current work to model these systems and integrate new recharge and rainfall data may lower estimates of what withdrawal levels will be sustainable. In these and other emerging situations, changing climate may well intensify water disputes that already tend to be the most difficult, unresolved public-policy issues in the islands. While some policy tools (such as the Public Trust and the Precautionary Principle) may help resolve these conflicts, it is likely that disputes will multiply and intensify as demand for water increases, possibly in the face of diminishing supply.